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The Doctor finds himself with a new companion, Donna, but she's late for her wedding. As the Tardis races to get to the church on time, the mysterious Empress joins the chase, and it becomes clear that Donna is the key to an ancient alien plan to destroy the Earth.

Notes

Catherine Tate to star in Doctor Who Christmas Special

Award-winning comedy actress Catherine Tate was unveiled tonight as the special guest star of the Doctor Who Christmas Special: The Runaway Bride due to transmit later this year on BBC One.

Making a surprise brief appearance in the final episode wearing full bridal wear, Catherine is set to play Donna, a runaway bride, in the Christmas Special alongside David Tennant (Doctor Who).

Catherine Tate says: "I'm honoured and delighted to be joining David Tennant aboard the Tardis. I was holding out for summer season at Wigan rep but as a summer job this'll do."

In tonight's heart-breaking series two climax, Rose (Billie Piper) said a tearful farewell to the Doctor after they had been separated in parallel worlds – lost forever in time and space - following a mighty war between the Cybermen and the Daleks.

Russell T Davies adds: "Doctor Who and Catherine Tate is just the most irresistible combination, a genuine treat for Christmas viewing.

"We filmed Catherine's appearance in tonight's episode many months ago, and I'm delighted the secret is out at last! But after two years of travelling with Rose, the Tardis is in for a bumpy ride with Donna on board."

Written by Russell T Davies, the Doctor Who Christmas Special: The Runaway Bride is currently in production. The producer is Phil Collinson and executive producers are Julie Gardner and Russell T Davies.

Freema Agyeman will join David Tennant as his new companion, Martha Jones when series three begins filming in Cardiff later this month.